An Intracellular Allosteric Modulator Binding Pocket in SK2 Ion Channels Is Shared by Multiple Chemotypes
An Intracellular Allosteric Modulator Binding Pocket in SK2 Ion Channels Is Shared by Multiple Chemotypes
复制标题
DOI：
10.1016/j.str.2018.02.017
复制
发表时间：
2018-04-03
期刊：
影响因子：
5.7
通讯作者：
Young, Gareth T.
中科院分区：
文献类型：
--
作者：
Cho, Lily T. -Y.;Alexandrou, Aristos J.;Young, Gareth T.
小电导钾（SK）离子通道通过传导后超极化电流来确定神经元的放电速率。它们是开发神经元放电率功能障碍的治疗方法的关键目标，例如癫痫，帕金森氏症和肌萎缩侧索硬化症（ALS）。在这里，我们的特点是位于SK2和钙调蛋白的细胞内界面的结合口袋，我们显示，由多个小分子化学型共享。该复合物的结晶显示，利鲁唑（批准用于ALS）和抗共济失调剂（4-氯-苯基）-[2-（3，5-二甲基吡唑-1-基）-嘧啶-4-基]-胺（CyPPA）的类似物与该位点结合并通过该位点进行变构调节。溶液状态核磁共振表明，利鲁唑，NS 309，和CyPPA类似物结合在这个二分口袋。我们证明，通过膜片钳电生理学，这两类配体相互作用重叠，但不同的残基在这个口袋里。这些数据确定了一个临床重要位点，为进一步研究利鲁唑和相关分子的作用机制奠定了基础。
Small conductance potassium (SK) ion channels define neuronal firing rates by conducting the after-hyperpolarization current. They are key targets in developing therapies where neuronal firing rates are dysfunctional, such as in epilepsy, Parkinson's, and amyotrophic lateral sclerosis (ALS). Here, we characterize a binding pocket situated at the intracellular interface of SK2 and calmodulin, which we show to be shared by multiple small-molecule chemotypes. Crystallization of this complex revealed that riluzole (approved for ALS) and an analog of the anti-ataxic agent (4-chloro-phenyl)-[2-(3,5-dimethylpyrazol-1-yl)-pyrimidin-4-yl]-amine (CyPPA) bind to and allosterically modulate via this site. Solution-state nuclear magnetic resonance demonstrates that riluzole, NS309, and CyPPA analogs bind at this bipartite pocket. We demonstrate, by patch-clamp electrophysiology, that both classes of ligand interact with overlapping but distinct residues within this pocket. These data define a clinically important site, laying the foundations for further studies of the mechanism of action of riluzole and related molecules.